The present invention relates generally to centrifugal dryers used to dry particulates entrained in a transport fluid and particularly to a seal assembly useful for preventing the transport fluid from reaching the bearing rotationally supporting the dryer shaft.
Centrifugal dryers are used to dry particulates, such as newly manufactured plastic spheres, for example. Representatively speaking, such dryers generally include a housing enclosing a cylindrical screen having a longitudinal axis. A rotor having a rotation axis coincident with the screen axis is mounted for rotation inside the housing.
A slurry including the particulates and a particulate entraining transport fluid, typically water, is delivered to the dryer through a conduit fluidly connected thereto at or near the bottom of the dryer. The slurry is usually delivered at a large flow rate to the dryer. As with any system where fluid transfer occurs in at high pressure and large flow rates and in association with moving parts, whether rotational or translational, leaks develop. In the case of a centrifugal dryer, these leaks can result in the accumulation of corrosive fluid in and around the bearing that rotationally supports the dryer rotor, thus shortening the life of the bearing and the dryer.
It would be desirable to have an improved seal that would substantially reduce the likelihood of fluid accumulating in and around a bearing that rotationally supports the rotor of a centrifugal dryer.
It is an object of the present invention to provide new and improved apparatus that is not subject to the foregoing disadvantages.
It is another object of the present invention to provide an improved end cap for a centrifugal dryer rotor that more successfully drains fluid away from bearing than prior art seals.
It is still another object of the present invention to provide an end cap for a centrifugal dryer than includes drainage ports.
The foregoing objects of the present invention are provided by an improved assembly for rotating and sealing a centrifugal dryer and a dryer including such a sealing assembly. A seal according to the present invention includes an end cap supporting a bearing that in turn rotationally supports a rotor. The end cap has an attachment portion, which in the embodiment of the invention shown herein is in the form of an annulus. The end cap further includes a seal ring including a groove receiving a v-ring seal that sealingly engages the stub shaft attached to the dryer rotor. The seal ring defines a drain cavity having at least one drain port out of which any fluid that gets by the v-ring seal can drain from the end cap. The drain port is disposed at a lower level than the v-ring seal and the grease seal so that fluid can drain away without accumulating and infiltrating past the bearing grease seal and into the bearing compartment formed between the end cap and rotor the stub shaft.
Stated otherwise, the present invention provides a rotor mount including a stub shaft and an end cap cooperating to define a bearing compartment and providing a seal against substantial intrusion of fluid into the bearing compartment and a drain for any fluid that does infiltrate past the seal. The aforesaid drain comprises at least a drain port disposed at a lower level than the grease seal for the bearing housed in the bearing compartment.
The foregoing objects of the invention will become apparent to those skilled in the art when the following detailed description of the invention is read in conjunction with the accompanying drawings and claims. Throughout the drawings, like numerals refer to similar or identical parts.